1. Field of the Invention
The present invention relates to a field-use hand-held apparatus for inspecting and cleaning optical fiber connector endfaces. More particularly, the invention relates to such an apparatus capable of interfacing with both male and female connectors with a relatively smaller set of adapting tips than prior art apparatus.
2. Description of the Related Art
In a typical optical fiber connector, an optical fiber has a terminal portion, which is surrounded by a ceramic ferrule. To couple the light from the fiber in one connector to the fiber in another connector, a mating adaptor is needed. This pair of connector ferrules can be accurately aligned (face to face) via a mating sleeve inside the connector mating adapter. We refer to an in-adaptor connector (i.e. the assembly with a connector that is plugged into an adaptor) as a ‘female’ connector; and refer to a free connector (not in an adaptor) as a ‘male’ connector. Up to date, a large variety of connector types have been developed and used in different applications.
The quality of fiber connector endfaces directly affects the optical fiber network performance. Dirt, grit and airborne contaminants can significantly increase the link insertion loss and decrease the return loss, thus causing network performance degradation and BER (Bit Error Rate) failure. According to the experience of fiber installation workers, dirty connector end-faces are a common problem found during troubleshooting of fiber links.
In principle, a new fiber patch cord from the cord manufacturer should come with clean connectors. But this may not always be guaranteed; and moreover the connector may be re-contaminated due to an improper action. For example, an endface being accidentally touched can cause significant dirt to be lodged on the connector endface. Such a dirty connector can further contaminate its mating connector, spreading the contamination. Therefore it is necessary for installers to always inspect each connector endface before inserting it into a mating adapter. If the connector is found dirty, cleaning the connector surface also becomes necessary.
There are several types of connector inspectors commercially available in today's market. For field use, portable inspectors mainly include Optical Microscopes (direct optical viewer) and Hand-Held Video Microscopes (consisting of an inspection probe and an LCD display, as shown in FIG. 1). Generally speaking, the Optical Microscope is for viewing Male connectors only (e.g. patch cords) because the object connector must be brought to the microscope site, i.e. close to your eye. Another drawback of Optical Microscope is the eye-safe issue when an operator directly peers at a fiber output surface and the fiber carries high optical power. To prevent any eye injury, some microscopes include a laser safety filter inside the optical path. Another solution is to build a miniature camera and micro display inside the microscope so as to avoid any direct contact between the light and operator's eye. But this solution does not help release the application limitation, i.e. you still have to bring the object connector close to your eyesight for inspection.
In comparison, Hand-Held Video Microscopes (see FIG. 1) are definitely eye-safe and much more flexible. A Hand-Held Video Microscope includes two primary parts: an inspection probe 70 and an LCD display 18′. They are connected by a long electrical cable 71. As the first primary part, the inspection probe can easily access locales a little distant from you or awkward to access. With this advantage, instead of bringing a connector to the scope, Hand-Held Video Microscopes can work for connectors that are affixed in a position and not movable. Most ‘female’ connectors belong to this category. With specially designed adapting tips for the Hand-Held Video Microscope probe, not only male connectors but also female connectors can be easily accessed and inspected. As different adapting tips should be mounted onto the probe for interfacing with different connectors, the Hand-Held Video Microscope manufacturers often offer a large family of adapting tips, with different ferrule sizes, different polishes (AC or APC), and different status (male or female). As the second primary part, the LCD display is not only ideal for eye safety but also much more flexible because it does not need to follow the probe to the connector accessing position. Besides, looking at a screen is much more comfortable than directly peering through a scope window. As an alternative configuration, a computer can replace the LCD unit, and the image shown on the computer can be processed and saved by using special software. In such a configuration, a video image capture device is generally needed between the probe and the computer.
Connector cleaners are also commercially available in different categories. Field-use cleaners for ‘male’ connectors include wipes (with or without a solvent), reel cleaners (cleaning tape cassettes), card cleaners (a sheet with multiple window slots), etc. As for field-use cleaners for ‘female’ connectors, the most popular tools are still swabs or sticks. Some semi-automated portable cleaning devices have also been released in recent years, e.g. the pen-type cleaner and the drill-type cleaner.
Although the importance of pre-inspection and cleaning has been widely recognized by installers, no product is yet available in today's market that can allow installers operating a single portable apparatus with multiple functions. U.S. Pat. No. 6,760,534 by Son disclosed a hand-held scope and cleaning tool. But it is not an eye-safe unit, and it can work for male connectors only.
Accordingly, it is the primary object of the present invention to provide a compact apparatus that allows multiple functions. A further object of the present invention is to provide an apparatus that is safe and flexible for users. Yet another object of the present invention is to provide an apparatus that is relatively simple and inexpensive.